Adverse events in US hospitals: A quarter of Medicare patients experienced harm in October 2018

Summary

In 2010, the US Department of Health and Human Services Office of Inspector General (OIG) reported the first national incidence rate of patient harm events in hospitals—27% of hospitalised Medicare patients experienced harm in October 2008. During that month, hospital care associated with these events cost Medicare and patients an estimated $324 million in reimbursement, coinsurance, and deductible payments. Nearly half of these events were preventable.

OIG conducted a new study to update the national incidence rate of patient harm events among hospitalised Medicare patients in October 2018. This work included calculating a new rate of preventable events and updating the cost of patient harm to the Medicare programme.

Content

Findings

Twenty-five per cent of Medicare patients experienced patient harm during their hospital stays in October 2018. Patient harm includes adverse events and temporary harm events.

Twelve per cent of patients experienced adverse events, which are events that led to longer hospital stays, permanent harm, life-saving intervention, or death. In addition to the patients who experienced adverse events, 13% of patients experienced temporary harm events, which required intervention but did not cause lasting harm, prolong hospital stays, or require life-sustaining measures. Temporary harm events were sometimes serious and could have caused further harm if providers had not promptly treated patients.

• Categories of Harm Events. The most common type of harm event was related to medication (43%), such as patients experiencing delirium or other changes in mental status. The remaining events related to patient care (23%), such as pressure injuries; to procedures and surgeries (22%), such as intraoperative hypotension; and to infections (11%), such as hospital-acquired respiratory infections.
• Preventability of Harm Events. Physician-reviewers determined that 43% of harm events were preventable, with preventable events commonly linked to substandard or inadequate care provided to the patient. (The overall harm rate would be 13% if we were to include only events that our physician-reviewers determined were preventable.) Reviewers determined that 56% of harm events were not preventable and occurred even though providers followed proper procedures. Events were determined not preventable for several reasons, including that the patients were found to be highly susceptible to the events because of their poor health status.
• CMS's Lists of Hospital-Acquired Conditions. CMS's two policies on hospital-acquired conditions (HACs) create payment incentives for harm prevention by reducing payment for certain HACs. However, because the policies use narrowly scoped lists of HACs and employ specific criteria for counting harm events, they have limited effectiveness in broadly promoting patient safety. The lists did not cover most of the harm events that patients in our study experienced. Of the harm events we identified, only 5% were on CMS's HAC Reduction Program list and only 2% were on CMS's Deficit Reduction Act HAC list.
• Harm Events Resulting in Costs to Medicare. Nearly a quarter of Medicare patients who experienced harm events (23%), either preventable or nonpreventable, required treatment that led to additional Medicare costs. These events also potentially increased patient costs in the form of coinsurance and deductible payments. Costs were incurred during the sample hospital stay or for an additional hospital stay necessary to ameliorate the harm. Combined, we estimated the costs for all events to be in the hundreds of millions of dollars for October 2018.